An organic light-emitting diode (OLED), also known as an organic electroluminescent device, has a basic structure including an anode, a cathode, and a light-emitting layer corresponding to each pixel region. When voltages are applied to an anode and a cathode, holes and electrons injected from the anode and the cathode may move to the light-emitting layer. The two charge carriers (i.e., holes and electrons) may be recombined in the light-emitting layer to generate an exciton (also known as an electron-hole pair), and the exciton in the material of the light-emitting layer may transit from an excited state to a ground state to emit light.
To improve the electron transport capability, an OLED may further include an electron transport layer disposed between the cathode and the light-emitting layer. The electron transport layer may enhance the electron mobility of the electron transport layer by doping an organic material with a metallic element. In existing technologies, the major organic material of the electron transport layer and the metal-ion containing complex are often co-evaporated. However, the ligand in the metal-ion containing complex has no contribution to the electron transport capability, thus imposing restrictions on the enhancement of the electron mobility of the electron transport layer.
According to the present disclosure, a vacuum evaporation device implementing co-evaporation of an organic material evaporation source and a metal evaporation source is highly desired, such that the co-evaporation of the organic material evaporation source and the metal evaporation source may be realized. Further, the evaporation rates of the organic material evaporation source and the metal evaporation source may be precisely controlled.
The disclosed vacuum evaporation devices and methods, and organic light-emitting display panels are directed to solving at least partial problems set forth above and other problems.